The present invention relates to a hemodialyzing unit that removes waste products on the blood from a patient suffering from renal insufficiency or the like, employing a hemodialysis membrane, and more particularly, to the hemodialyzing unit that is applied to a case where dialysis is difficult to perform at a general flow rate of dialytic fluid, and a dialytic fluid circuit for the same.
When hemodialysis is conducted employing an artificial dialyzer, a blood pump and a dialytic fluid pump are controlled in a hemodialyzing unit as follows. The blood pump is controlled so that the flow rate of blood circulating in a blood circuit is constant. The dialytic fluid pump is controlled so that the flow rate of dialytic fluid in contact with the blood through a hemodialysis membrane is constant similarly (by a single-path method). According to the hemodialysis, substances are transferred between the dialytic fluid and the blood, thereby removing moisture or waste products in the blood. The removed quantity is closely related to the blood flow rate and the flow rate of dialytic fluid. According to the general hemodialysis treatment (hemodialyzing unit), the flow rate of dialytic fluid is 500 ml/min, and can be decreased so far as to reach a level of 300 ml/min.
However, the general hemodialysis cannot be applied to types of patients and cases such as a patient who tends to be in disequilibrium syndrome, a case of a renal disease having a complication of a circulatory system or a case of a multiple organ failure. For these patients and cases, the application of a Continuous Hemo Dialysis (CHD), a Continuous Hemo Filtration (CHF), and a Continuous Hemo Dia-Filtration (CHDF) has been studied and exhibits some effects. The CHD and CHDF are characterized by continuously and slowly conducting water removal or fluid supply. However, according to these methods, it is difficult to adjust the flow rate in a low flow rate range in the general hemodialyzing unit or a dialytic fluid supply unit. Therefore, the CHD or CHDF requires a device for the exclusive use, and further, supplemental fluid for a filtering-type artificial kidney to be given.
Therefore, with the foregoing in mind, it is an object of the present invention to provide a hemodialyzing unit that can be used at a low flow rate of dialytic fluid, by which a wide range of treatments of the CHD (or CHDF), SHD (or SHDF), and HD (or HDF) can be conducted without employing a special device for the exclusive use required for conducting the CHD or CHDF. Moreover, it is an object of the present invention to provide a hemodialyzing unit for conducting these treatments at low cost, and a dialytic fluid circuit for the same.
It should be noted that the SHD designates Slow Hemo Dialysis and the SHDF designates Slow Hemo Dia-Filtration in the specification, which are conducted at a low flow rate of dialytic fluid. More specifically, the SHD and the SHDF refer to the dialysis in which a dialytic fluid has a decreased flow rate, so as to be flowed slowly, whereby the water removal or the substance transfer is performed slowly.
The above-mentioned treatment is applied to a linking (intermediate) treatment for a patient having serious renal insufficiency when the treatment is shifted from the CHD (or CHDF) to the HD (or HDF). According to the treatment, the flow rate of dialytic fluid is in a range of about 10 to 250 ml/min (not exceeding 300 ml/min to be the lowest flow rate for the general dialyzing unit). One dialysis period (treatment period) is about 4 or 5 hours to 8 hours, similarly to the case of the general dialysis. It does not take as long as the case of the CHD, which takes 12 to 24 hours.
It is another object of the present invention to provide a hemodialyzing unit that can be applied to both cases of the general hemodialysis and the hemodialysis at a low flow rate of dialytic fluid. To be specific, the present invention aims to provide a hemodialyzing unit that can be used for the general hemodialysis in a usual mode, and, if required, can be used for conducting a wide range of treatments, such as CHD (or CHDF), SHD (or SHDF), and HD (or HDF) by a minor change in the device configuration.
The hemodialyzing unit of the present invention includes a dialytic fluid supply line for feeding a dialytic fluid from a dialytic fluid supply/discharge unit to a dialyzer, a dialytic fluid discharge line for feeding a dialytic fluid discharged from the dialyzer to the dialytic fluid supply/discharge unit, and a bypass line for connecting both the lines at the respective intermediate portions. Accordingly, the dialytic fluid supply line includes an upstream supply line extending from the dialytic fluid supply/discharge unit to a coupling portion to the bypass line and a downstream supply line extending from the coupling portion to the bypass line to the dialyzer. Further, the dialytic fluid discharge line includes an upstream discharge line extending from the dialyzer to the coupling portion to the bypass line and a downstream discharge line extending from the coupling portion to the bypass line to the dialytic fluid supply/discharge unit. The downstream supply line is provided with a flow rate adjusting member.
As described above, the downstream supply line is provided with the flow rate adjusting member, thereby controlling the flow rate of the dialytic fluid flowing into the dialyzer. Since the general dialytic fluid supply/discharge unit cannot adjust the dialytic fluid to be fed to the dialytic fluid supply line at a low flow rate, the normal flow rate of dialytic fluid flows into the upstream supply line. In contrast, the downstream supply line is additionally provided with the flow rate adjusting member, whereby the flow rate of dialytic fluid is controlled to be low, and consequently, the dialytic fluid can be fed to the dialyzer at a low flow rate. The dialytic fluid that passes through the upstream supply line, not to be fed to the dialyzer, becomes a redundant dialytic fluid. The redundant dialytic fluid passes through the bypass line, and then the downstream discharge line, to be discharged from the dialytic fluid supply/discharge unit.
Any flow rate adjusting member may be used as long as it suitably adjusts the flow rate of dialytic fluid of the downstream supply line, preferably having a simple structure. For instance, the flow rate adjusting member can be composed of a dialytic fluid feed pump, or a dialytic fluid feed pump and a pump tube attached thereto. Moreover, it is preferable that the flow rate adjusting member can adjust the flow rate of dialytic fluid in a lower flow rate range than the dialytic fluid supply/discharge unit. There is no particular limit to the dialytic fluid feed pump; however, in general, a roller pump or a peristaltic pump, or the like is employed, for instance.
Moreover, in the hemodialyzing unit having the above-mentioned configuration, it is more preferable to control the dialytic fluid feeding rate through the upstream supply line to be larger than that through the downstream supply line.
Therefore, it is preferable for the hemodialyzing unit of the present invention to employ a dialytic fluid feed pump capable of adjusting the flow rate to be 150 ml/hr. In view of the upper limit of the flow rate of dialytic fluid, it is preferable to adjust the flow rate of dialytic fluid in a range of the lowest dialytic fluid feeding rate of 150 ml/hr to the highest dialytic fluid feeding rate of 30,000 ml/hr. If it is desired to accurately control the dialytic fluid feeding rate in a low flow rate range, it is preferable to use the pump having a controllable range in the lowest flow rate of dialytic fluid of 150 ml/hr to the highest flow rate of dialytic fluid of 9,000 ml/hr. Moreover, the use of the dialytic fluid feed pump, to which pump tubes having different diameters can be attached, allows the flow rate setting range to be varied by exchanging the pump tube. The general dialysis can be conducted sufficiently at the lowest flow rate of dialytic fluid of 500 ml/min. Accordingly, in the usual case, a pump tube suitable for the set flow rate is attached to the dialytic fluid feed pump, and in the case where the flow rate is required to be set lower, the pump tube having a smaller diameter may be employed.
Further, in the hemodialyzing unit having the above-described configuration, it is preferable to provide at least one open/close member to the upstream supply line and the downstream discharge line, respectively, thereby ensuring safety of the patient To be specific, when the dialytic fluid feeding system or the dialytic fluid discharge system of the dialytic fluid supply/discharge unit falls into an abnormal condition, the respective open/close members provided on both the lines are closed. Therefore, the connection to the dialytic fluid supply/discharge unit is cut off so as to form a recirculating loop defined by the downstream supply line, the upstream discharge line, and the bypass line.
Further, it is preferable to provide an open/close member such as a solenoid valve or the like to the bypass line. Therefore, the normal channel of the dialytic fluid circuit (defined by the dialytic fluid supply/discharge unit, the dialytic fluid supply line, the dialyzer, the dialytic fluid discharge line, and the dialytic fluid supply/discharge unit) can be selected without using a closing member such as a forceps, or a mode in which the dialytic fluid flows at a low flow rate can be selected. Moreover, when the open/close member is provided to the bypass line, the line can be cleaned/disinfected. When the solenoid valve is employed as the open/close member, the solenoid valve is incorporated in the dialyzing unit so as to switch automatically between the dialysis and the cleaning. According to the use state, a hand-operated valve may be employed instead of the solenoid valve. As described above, the circuit for the dialytic fluid at a low flow rate previously is incorporated in the dialyzing unit, whereby the switching among the HD, SHD, CHD, and the like can be simplified. Therefore, the emergency case can be managed with ease.
When a sodium injecting unit is provided to the dialytic fluid supply/discharge unit, dialysis of high sodium at a low flow rate can be realized, which was not easily conducted by the device for the exclusive use of the CHD or CHDF.
The following configuration allows a hemodialyzing unit to conduct the general hemodialysis in a usual mode, and, only when required, to set the dialytic fluid at a low flow rate. To be specific, the hemodialyzing unit having any of the above-described configurations is configured so that complementary connector pairs are provided to the respective lines of the upstream supply line, the downstream discharge line, the downstream supply line extending from the attachment portion of the flow rate adjusting member to the dialyzer and the upstream discharge line, respectively, in order to disconnect/reconnect the respective lines at each complementary connector pair.
For instance, the upstream supply line extending from the first open/close member provided at the upstream supply line to the dialytic fluid supply/discharge unit is provided with a first complementary connector so as to be disconnected/reconnected. The downstream discharge line extending from the second open/close member provided at the downstream discharge line to the dialytic fluid supply/discharge unit is provided with a second complementary connector so as to be disconnected/reconnected. The downstream supply line extending from the attachment portion to the flow rate adjusting member to the dialyzer is provided with a third complementary connector so as to be disconnected/reconnected. The upstream discharge line is provided with a fourth complementary connector so as to be disconnected/reconnected.
The hemodialyzing unit includes two devices and circuit configurations. One device body or circuit body includes the dialytic fluid supply line for feeding the dialytic fluid from the dialytic fluid supply/discharge unit to the dialyzer, and the dialytic fluid discharge line for feeding the dialytic fluid discharged from the dialyzer to the dialytic fluid supply/discharge unit. The dialytic fluid supply line includes a first detachable portion composed of a complementary connector pair at the intermediate portion so as to be disconnected/reconnected by detachment of the complementary connector pair at the first detachable portion. The dialytic fluid discharge line includes a second detachable portion composed of a complementary connector pair at the intermediate portion so as to be disconnected/reconnected by detachment of the complementary connector pair at the second detachable portion.
Further, the other unit or circuit includes a dialytic fluid supply extension-line, a dialytic fluid discharge extension-line, and a bypass line for connecting both the extension lines at each intermediate portion. Complementary connectors are disposed at both the ends of the dialytic fluid supply extension-line so as to be connected to each of the disconnected complementary connectors of the first detachable portion in the above configuration. Complementary connectors are disposed at both the ends of the dialytic fluid discharge extension-line so as to be connected to each of the disconnected complementary connectors of the second detachable portion. A flow rate adjusting member is provided between the coupling portion to the bypass line of the dialytic fluid supply extension-line and one end of the dialytic fluid supply extension-line. Thus, a unit can be configured to serve as an incorporation dialytic fluid circuit.
In the case where the general hemodialysis is conducted in those configurations, a hemodialyzing unit including the first detachable portion and the second detachable portion is used while the respective detachable portions are connected. In this case, the hemodialyzing unit configured as described above can be used in the same manner as the general hemodialyzing unit.
When the dialytic fluid needs to flow into the dialyzer at a low flow rate, the respective complementary connectors of the first and second detachable portions are disconnected. Then, the dialytic fluid supply extension-line is inserted into the dialytic fluid supply line, and the dialytic fluid discharge extension-line is inserted into the dialytic fluid discharge line. Thus, a hemodialyzing unit, in which the incorporation dialytic fluid circuit is inserted, can be formed. In this state, the flow rate adjusting member provided at the dialytic fluid supply line reduces the flow rate of the dialytic fluid flowing into the dialyzer (i.e., the flow rate of the dialytic fluid passing through the downstream supply line). However, there is no change in the flow rate of the dialytic fluid flowing from the dialytic fluid supply/discharge unit to the dialytic fluid supply line. Therefore, the redundant dialytic fluid passes through the bypass line, and then, through the downstream discharge line, to be discharged from the dialytic fluid supply/discharge unit. According to the above-described system, only when required, the flow rate of the dialytic fluid passing through the dialyzer can be adjusted to be low, simply and exactly.
The hemodialyzing unit configured as described above may be configured including a flow rate adjusting line, a blood circuit connecting line, and a control unit as follows. The flow rate adjusting line arranged in parallel to the dialytic fluid discharge line includes a first flow rate adjusting unit for adjusting the flow rate of dialytic fluid. The blood circuit connecting line including a second flow rate adjusting unit for adjusting the flow rate of dialytic fluid is provided so as to connect the bypass line to the blood circuit. The control unit for controlling the first and second flow rate adjusting units is provided so that the flow rate of dialytic fluid through the flow rate adjusting line is equal to that through the blood circuit connecting line. According to the above configuration, an on-line HDF (Hemo Dia-Filtration) can be conducted at a low flow rate of dialytic fluid.